Homemade bug spray is easy to make and use.  Just fill a small spray bottle with about a cup of vodka (yes, the kind people drink).  Any brand will work; I use the cheap stuff because it's only for the bugs. Then you add about 20 drops of citronella essential oil and 10-20 more of lemon essential oil.  This keeps best in the fridge and I just make a small amount up as we go.  

It's especially nice because I don't worry about harmful chemicals in my kids eyes or on their skin.  A little bit goes a long way so this will save you a lot of money in the long run.   And it keeps the bugs off even in the swampy woods of Michigan.